JP2014006218A - Particle counting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique suitable for monitoring a clean state while collecting particles and measuring the number of particles in air.SOLUTION: A particle counting system 1 comprises a collection device 2, liquid loading/unloading operation execution means and a particle counting device 4. The collection device 2 performs collection operation to absorb circumambient air into a container storing liquid and to collect particles in the air in the liquid. The liquid loading/unloading operation means sequentially executes liquid loading/unloading operation to discharge the liquid, after the collection operation, from the collection device 2 while supplying the collection device 2 with additional liquid for succeeding collection operation. The particle counting device 4 measures the number of particles contained in the liquid discharged from the collection device 2 along with the sequential liquid loading/unloading operation.

Description

  The present invention relates to a particle counting system for measuring the number of particles after collecting particles in the air in a liquid.

In general, electronic devices such as semiconductors and pharmaceuticals are manufactured in a clean room. Since electronic devices, pharmaceuticals, and the like adversely affect performance and quality due to adhesion of fine particles and microorganisms during the manufacturing process, it is preferable that the clean room be kept as dust-free and aseptic as possible.
For this reason, conventionally, a method of measuring particles floating in a clean room using a particle counter and monitoring the clean state in the clean room has been used.

  Regarding the measurement of particles floating in the clean room, a first prior art using an air particle counter is known (see, for example, Patent Document 1). The first prior art is characterized in that a scroll pump and a photomultiplier tube are provided in the air particle counter, thereby measuring the number of particles contained in the atmosphere at a maximum flow rate of 100 L / min. be able to.

In addition, a second prior art is known in which particles in the atmosphere are collected by a collector before the particles are measured by a particle counter (see, for example, Patent Document 2). In this prior art, a liquid is injected into a container of a collector, the air is sucked into the collector (container), and particles contained in the sucked air are taken into the liquid by a centrifugal separation method. .
According to the second prior art, not only the air can be sucked in a flow rate range of 200 L / min to 400 L / min, but also the sucked air particles can be collected in 10 mL of liquid.

  In addition to the second prior art, a third prior art for measuring the number of particles after collecting particles in the air in a liquid is known (see, for example, Patent Document 3). In this prior art, water is stored in a microorganism analysis apparatus, and air (inhaled) is passed through the water to mix microorganisms and fine particles in the air with water. Then, laser light is irradiated to water mixed with microorganisms and fine particles, and the microorganisms are measured using the autofluorescence phenomenon.

Special table 2009-539084 gazette Japanese Patent No. 4571623 Japanese Patent No. 3745719

  In recent years, it has been possible to collect as many samples (atmosphere) as possible in a short time and to measure the number of particles contained in the collected samples in real time from the viewpoint of more efficiently monitoring the clean state in a clean room. It is desired. The above-mentioned first to third prior arts are all assumed to be timely measured at a place to be measured, and are suitable for applications in which particles at a measurement place are automatically measured over a long period of time. Not.

  Further, from the viewpoint of collecting and measuring a large amount of samples, the above-described first to third prior arts have the following problems.

  That is, in the first prior art relating to the air particle counter, if the measurable atmospheric flow rate is increased, the measurement time is increased accordingly. Further, when the flow rate of the atmosphere is increased, the inner diameter of the flow cell is expanded corresponding to this flow rate, so that it is necessary to expand the particle detection region, and thus the irradiation range of the laser beam must be expanded. In this case, since the energy density of the laser light is reduced by extending the laser light irradiation range, there arises a problem that the detection sensitivity is lowered.

  On the other hand, in order to maintain the detection sensitivity by increasing the flow rate in the flow cell while increasing the air flow rate, the energy density of the laser beam must be maintained. In this case, a high-power laser light source corresponding to the above irradiation range is required. Alternatively, a highly sensitive light receiving element is required. However, if a high-power laser light source or a high-sensitivity light receiving element is used, the cost increases accordingly.

  As described above, it is very difficult to maintain the detection sensitivity with respect to the particle diameter while collecting a large amount of samples using the air particle counter, and it is technically difficult to achieve the harmony between them. It will be high. Therefore, the first prior art is not suitable for the purpose of automatically measuring particles at a measurement place for a long time while collecting a large amount of sample.

On the other hand, in the method of measuring particles collected in a liquid, the amount of air suction (flow rate) can be increased without increasing the amount of liquid as a sample.
For this reason, the second prior art is suitable for collecting a large amount of sample. However, when measuring a sample with a particle counter, an operator removes the container of the collector and puts it in the particle counter. Must be installed. For this reason, the second prior art is unsuitable for so-called constant monitoring in which the transition of the number of particles is monitored over a long period of time (for example, 24 hours).

  In the third prior art, it is possible to measure the atmospheric state at a specific time batchwise, but it is not possible to measure the change in the number of particles as seen in time series. Therefore, like the second prior art, the third prior art is not suitable for constant monitoring.

  Therefore, the present invention provides a technique suitable for monitoring a clean state regarding collection of particles contained in the air and measurement of the number of particles.

  In order to solve the above-mentioned problems, the following solutions are adopted.

  That is, the present invention provides a particle counting system. This particle counting system includes an air particle collector that collects air in a container containing liquid and collects air particles with the liquid, and an air particle collector. On the other hand, a liquid input / output operation executing means for executing a series of liquid input / output operations for discharging the liquid after the collection operation from the air particle collector while supplying a new liquid for the collection operation, and a series of liquid input / output The liquid particle counter which measures the number of the particles contained in the liquid discharged | emitted from the air | atmosphere particle | grain collector with operation | movement is provided.

  According to the present invention, the supply of the liquid to the air particle collector and the discharge of the liquid from the air particle collector are performed as the liquid in / out operation. That is, since the supply of the liquid and the discharge of the liquid can be controlled automatically, it is suitable for constant monitoring of the clean state in a clean room, for example. Moreover, the liquid discharged | emitted from the air | atmosphere particle | grain collector is immediately poured into a particle | grain counter. For this reason, the particle counter in liquid can measure the particles in the air in real time.

Note that the air particle collector preferably collects air particles as a liquid by a centrifugal separation method. Thereby, for example, as compared with a method of storing particles in the air sent by a pump as in Patent Document 3, the air particle collector collects particles of less than 1 μm in a liquid. Therefore, the particle collection efficiency can be improved accordingly.
The submerged particle counter may be, for example, a biological particle counter that measures the number of biological particles from particles contained in the liquid. In this case, the liquid particle counter can detect the fluorescence emitted from the biological particles using the autofluorescence phenomenon. Thereby, the measurement of the number of biological particles floating in the clean room and the transition of the number can be monitored.

  The liquid input / output operation executing means includes a liquid container for storing a new liquid supplied to the air particle collector, and a first flow path for flowing the liquid from the liquid container toward the air particle collector. A second flow channel for flowing the liquid discharged from the air particle collector toward the liquid particle counter, and a third channel for flowing the liquid after the number of particles is measured by the liquid particle counter. And a pump that is disposed on the third flow path and moves the liquid from the second flow path to the third flow path via the liquid particle counter, and traps air particles by the liquid container. A flow rate controller for controlling the amount of liquid supplied to the collector and the flow rate of the liquid from the second flow path to the third flow path via the liquid particle counter by the pump.

In the particle counting system of the present invention, the liquid container and the air particle collector are connected by the first flow path. The air particle collector and the liquid particle counter are connected by the second flow path.
The flow control device controls the supply of liquid from the liquid container to the air particle collector and the supply of liquid from the air particle collector to the liquid particle counter.
For this reason, after the collection of particles by the air particle collector is completed, it is not necessary for the operator to install the collected sample in the liquid particle counter, from the collection of particles to the measurement of the number of particles. Can be done automatically. In the liquid particle counter, the particles collected by the air particle collector can be measured.

The pump also causes the liquid to flow at a flow rate less than the flow rate of air taken into the container of the air particle collector.
Thereby, the submerged particle counter which measures with a general flow volume can be used. In addition, the liquid particle counter can always measure the number of particles contained in the liquid at a constant flow rate without depending on the flow rate of the air sucked by the air particle collector. Note that the amount of liquid sucked by the pump may be controlled using a valve.

  In the particle counting system of the present invention, the flow control device operates the pump while supplying a new liquid to the liquid container in the process of collecting by the air particle collector. The liquid after the collection operation is discharged from the air particle collector to the second flow path.

That is, “collection of particles by air particle collector” and “measurement of particles by submerged particle counter” can be performed simultaneously. Therefore, the transition of the number of particles floating in the clean room can be monitored by continuously measuring for a predetermined time (for example, 24 hours).
In addition, since the liquid collected by the air particle collector is immediately supplied to the liquid particle counter,
The liquid particle counter can measure the increase / decrease tendency of the number of particles in the air in real time.

The flow control device may discharge the liquid after the collection operation from the air particle collector to the second flow path after the collection operation by the air particle collector is completed.
Even in this case, it is not necessary for the operator to attach the sample (liquid containing particles) collected by the air particle collector to the liquid particle counter. For this reason, for example, in order to examine the transition of the number of particles floating in the clean room, it is possible to perform intermittent measurement such as measurement for 30 minutes at intervals of 1 hour for 24 hours.

  Further, as another aspect of the above intermittent measurement, for example, it is also suitable for measuring the number of particles contained in a predetermined amount of air such as 600L or 1500L. Even in this case, since it is not necessary for the operator to attach the sample collected by the air particle collector to the liquid particle counter, for example, measurement is performed in a shorter time than the technique of Patent Document 1. be able to.

In the particle counting system of the present invention, the liquid input / output operation executing means further includes a liquid amount sensor that is disposed on the first flow path and detects the amount of liquid supplied to the air particle collector. At this time, the flow controller controls the amount of liquid supplied to the air particle collector by the liquid container based on the amount of liquid detected by the liquid amount sensor.
Thus, the liquid in the air particle collector can be maintained at a constant amount by using the liquid amount sensor.

According to the particle counting system of the present invention, particles in the air can be collected efficiently and measurement can be performed automatically. Further, even if the flow rate of air sucked by the air particle collector is increased, it is not necessary to increase the flow rate of the liquid measured by the liquid particle counter in accordance with this. Therefore, the measurement time of the number of particles for a predetermined amount of air can be shortened compared with the measurement of the number of particles using an air particle counter.
In addition, since the collection of particles in the air to the measurement of the number of particles are automatically performed, the method is also suitable for a monitoring method in which the increase / decrease tendency of the number of particles is constantly monitored.

It is a figure showing roughly the composition of the particle counting system in one embodiment. It is a figure which shows schematically the structure inside a particle | grain counting part. It is a block diagram for demonstrating the flow of control by the flow control part of this embodiment. It is a flowchart which shows the procedure of a continuous measurement. It is a graph which shows transition of the number of particles measured by continuous measurement. It is a flowchart which shows the procedure of intermittent measurement. It is a graph which shows transition of the amount of liquids in a container main part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment
FIG. 1 is a diagram schematically illustrating a configuration of a particle counting system 1 according to an embodiment.
A particle counting system 1 shown in FIG. 1 is applied to, for example, a clean room where electronic devices, pharmaceuticals, and the like are manufactured.

  The particle counting system 1 has an air particle collector 2 (hereinafter referred to as a collector 2) as a configuration for collecting particles in the air, and measures the number of collected particles. For this purpose, the liquid particle counter 4 (hereinafter referred to as particle counter 4) is included.

[Airborne particle collector]
The collector 2 performs a collecting operation of taking ambient air into a container containing the liquid and collecting particles in the air with the liquid. In the present embodiment, the collector 2 collects particles in the air as a liquid by a centrifugal separation method. The collector 2 has a container body (container) 6 and an aspirator 8, which are connected to both ends of a U-shaped tube 10.

The container main body 6 includes a cylindrical main body portion 6a and a bottom portion 6b having a truncated cone shape, and these serve as a centrifuge chamber.
A cap-shaped lid portion 6c is fitted into the main body portion 6a. The upper surface of the lid portion 6c is connected to the tube 10, and an opening 6d for sucking outside air is formed on the peripheral surface.
Liquid (pure water) is stored in the bottom 6b. In the present embodiment, the amount of liquid stored in the container body 6 (bottom portion 6b) is, for example, about 10 mL.

  The suction device 8 is a device that sucks air in the container body 6, and sucks air in the container body 6 through the tube 10. At this time, external air is taken into the container body 6 from the opening 6d formed in the lid 6c. A spiral air flow is formed in the container body 6 along the inner wall by the suction device 8. At this time, the particles in the container body 6 are centrifuged and collected in a liquid. The flow rate of air taken into the container body 6 by the suction device 8 is, for example, 300 L / min.

(Liquid particle counter)
The particle counter 4 measures the number of particles contained in the liquid discharged from the collector 2.
A plurality of display lamps 4a are attached to the surface of the case of the particle counter 4. The display lamps 4a indicate, for example, the power supply state (On or Off), the measurement state, the connection state to the network, and the like. indicate.

Further, the particle counter 4 includes a particle counter 4b that measures the number of particles collected in the liquid by the collector 2. In FIG. 1, the particle counting unit 4b is not shown.
The particle counting unit 4b irradiates the liquid containing the target object (particles) flowing in the flow cell with light, detects scattered light from the target object, and counts the number of detected scattered light.
In the particle counter 4b, the number of biological particles can also be measured. In this case, the particle counting unit 4b irradiates the liquid containing the objects (biological particles and non-biological particles) flowing in the flow cell with ultraviolet rays, and separates and extracts the autofluorescence emitted from the biological particles with a dichroic mirror or an optical filter. , Count that number.

FIG. 2 is a diagram schematically showing the internal configuration of the particle counting unit 4b.
The particle counter 4b includes a light emitting device 12, an irradiation optical lens system 14, a flow cell 16, a first condensing optical lens system 18, a light shielding device 20, and a second condensing optical lens system as a configuration for detecting scattered light. 22 and a light receiving device 24 for scattering.

[Light emitting device]
The light emitting device 12 is constituted by, for example, a semiconductor laser diode (including a semiconductor LED element; hereinafter referred to as a laser diode). The laser diode 12 irradiates a liquid (pure water) containing particles with laser light 12a.

[Irradiation optical lens system]
The irradiation optical lens system 14 is composed of, for example, a plurality of types of optical lenses. For example, it is composed of a collimator lens, a biconvex lens, and a cylindrical lens, and irradiates the object with laser light 12a oscillated from the laser diode 12.

[Flow cell]
The flow cell 16 is composed of, for example, a hollow quadrangular cylinder 16a made of synthetic quartz, sapphire, or the like, and a liquid (pure water) 28 containing particles 26 as an object flows from the bottom to the top. It has a structure to do. The laser beam 12a is applied to a hollow region in which the liquid (pure water) in the cylindrical portion 16a flows to form a detection region.

  These lights are detected by the light receiving device 24 for scattering through the plurality of one condensing optical lens system 18 and the second condensing optical lens system 22. The intensity of the scattered light, that is, the amount of scattered light depends on the size of the particle 26, and the larger the amount, the larger the amount of light. Moreover, if the laser output is increased and the flow cell 16 is irradiated with a large amount of laser light 12a, the scattered light from the particles 26 will increase.

[Shading device]
The light shielding device 20 is composed of, for example, a laser trap (hereinafter referred to as a laser trap 20). The laser trap 20 shields the laser light 12 a oscillated from the laser diode 12 and passed through the flow cell 16.

[First condensing optical lens system]
The 1st condensing optical lens system 18 is comprised from the some optical lens, for example. The first condensing optical lens system 18 is installed at a position having an angle of about 90 degrees with respect to the traveling direction (optical axis) of the laser light 12a. The scattered light from the particles 26 in the flow cell 16 is collected by the first condensing optical lens system 18.
In order to collect as much side scattered light from the particles 26 as possible, it is preferable that the lens diameter is large, and it is determined according to the position (distance) provided with the detection device for detecting the scattered light from the particles 26. Is done.

[Second condensing optical lens system]
The second condensing optical lens system 22 is composed of, for example, a plurality of optical lenses. The second condensing optical lens system 22 is installed on the traveling direction (optical axis) of the light transmitted through the first condensing optical lens system 18. The scattered light transmitted through the first condensing optical lens system 18 is collected by the second condensing optical lens system 22 and imaged on the incident surface of the light receiving device 24 for scattering.

[Light scattering device]
The scattering light receiving device 24 is constituted by, for example, a photodiode or a photomultiplier, and receives the scattered light of the particles 26 that has passed through the second condensing optical lens system 22. The light received by the scattering light receiving device 24 is converted into an electrical signal corresponding to the light amount, and the electrical signal is output from the scattering light receiving device 24. Based on the output signal from the light receiving device 24 for scattering, the number of particles is measured by a counting system (not shown).

[Liquid entry / exit operation execution means]
Further, the particle counting system 1 of the present embodiment shown in FIG. 1 includes a liquid in / out operation executing means. The liquid in / out operation executing means executes a series of liquid in / out operations for discharging the liquid after the collecting operation from the collector 2 while supplying a new liquid to the collector 2 for the collecting operation.
As a configuration for realizing this, the liquid input / output operation executing means includes a liquid container 30, a pipe 32 as a first flow path, a pipe 34 as a second flow path, a tube 36 as a third flow path, And a pump 38. Further, the liquid in / out operation executing means has a flow rate control device 40.

[Liquid container]
The liquid container 30 stores a new liquid supplied to the collector 2. A predetermined amount of liquid is stored in the liquid container 30 in advance, and an appropriate amount of liquid is supplied from there to the collector 2. The amount of the liquid stored in the liquid container 30 can be freely set by the operator according to, for example, the flow rate of the liquid flowing in the particle counter 4 or the time required for measuring the number of particles.
In the present embodiment, for example, the liquid container 30 applies pressure to cause the liquid to flow toward the collector 2. Or you may make it flow using gravity.

[First channel]
The pipe 32 connects the liquid container 30 and the collector 2, and allows the liquid to flow from the liquid container 30 toward the collector 2.
A liquid amount sensor 42 is attached to the pipe 32. The liquid amount sensor 42 detects the amount of liquid supplied to the collector 2. For example, the flow control device 40 is configured to supply the liquid supplied from the liquid container 30 based on a signal output from the liquid amount sensor 42 so that the liquid supplied into the collector 2 becomes a predetermined amount (10 mL). Control the amount.

[Second channel]
The pipe 34 connects the collector 2 and the particle counter 4 and causes the liquid discharged from the collector 2 to flow toward the particle counter 4.

[Third flow path]
The tube 36 connects the particle counter 4 and the pump 38, and allows the liquid to flow after the number of particles is measured by the particle counter.

〔pump〕
The pump 38 causes the liquid to flow from the pipe 34 to the tube 36 via the particle counter 4. The pump 38 has a roller 38a, and a tube 36 is wound around the roller 38a. Hereinafter, the pump 38 is referred to as a roller pump 38. In this embodiment, the pump is not limited to the roller pump 38, and other types of liquid suction pumps may be used as long as the desired conditions are satisfied.

  The roller pump 38 rotates the roller 38a. As the roller 38a rotates, the tube 36 is pressed and the liquid in the tube 36 flows. When the rotation of the roller 38a is stopped, the liquid in the tube 36 and the liquid in the pipe 34 are also stopped.

The liquid in the container body 6 is sent to the particle counter 4 through the pipe 34 and is sent from the particle counter 4 to the roller pump 38 through the tube 36 and is discharged outside as waste liquid.
The tube 36 may be provided with a valve 44 in order to adjust the flow rate of the liquid discharged from the container body 6. However, if the roller pump 38 can flow the liquid at a predetermined flow rate (for example, 10 mL / min), the valve 44 may not be provided. Further, the roller pump 38 can be incorporated in the particle counter 4.

[Flow control device]
The flow rate control device 40 (hereinafter referred to as the controller 40) is configured to supply the liquid to the collector 2 by the liquid container 30 and the flow rate of the liquid from the pipe 34 to the tube 36 via the particle counter 4 by the roller pump 38. To control.
In the particle counting system 1 of the present embodiment, the liquid container 30, the collector 2, the particle counter 4, and the roller pump 38 are electrically connected to the controller 40 via a network cable 46. In addition, a liquid amount sensor 42 and a valve 44 are connected to the controller 40 via a network cable 46.

  The controller 40 is equipped with a display 40a for displaying a measurement state to an operator and an operation panel 40b for setting conditions for measuring particles by the particle counter 4.

  The controller 40 generates an alarm when a preset value is exceeded. Thereby, it can inform an operator that abnormality has occurred in the clean state in the clean room, for example.

  In the present embodiment, the controller 40 includes a flow rate control unit 40c. In addition, illustration of the flow control part 40c is abbreviate | omitted in FIG.

[Flow control by controller]
FIG. 3 is a block diagram for explaining the flow of control by the flow rate controller 40c of the present embodiment. In addition, the white arrow shown in FIG. 3 represents the flow of the liquid. Further, the black arrow represents the flow of control by the flow rate control unit 40c.

[Supply of liquid to air particle collector]
The flow control unit 40 c outputs a signal indicating that the liquid supply to the liquid container 30 is started. When the signal is input, the liquid container 30 starts supplying the liquid to the container body 6.
At this time, the liquid container 30 can supply the liquid to the container body 6 by a method of applying pressure to the liquid by a pressurizing means (not shown). Moreover, the liquid container 30 can also supply a liquid to the container main body 6 by the method of flowing a liquid using gravity.
Further, the liquid container 30 supplies a predetermined amount of liquid (for example, 10 mL) to the container body 6 according to the input signal, or continuously supplies the liquid at a predetermined flow rate (for example, 10 mL / min).

Further, the liquid quantity sensor 42 is disposed in the pipe 32, and an electric signal output from the liquid quantity sensor 42 is output to the flow rate control unit 40c.
In this case, the flow controller 40c may control the amount of liquid supplied from the liquid container 30 to the container body 6 based on the input electrical signal. The liquid amount sensor 42 may output the above signal to the liquid container 30. In this case, the liquid container 30 controls the supply amount of the liquid based on the input electric signal.

[Participation of particles by air particle collector]
The flow control unit 40c outputs a signal indicating that the collector 2 starts to suck air. When the above signal is input, the collector 2 sucks air and collects the particles contained therein in the liquid supplied from the liquid container 30.

Specifically, the ambient air is taken into the container body 6 by first operating the suction device 8. At this time, the suction device 8 sucks air at a flow rate of, for example, 300 L / min.
The air taken into the container main body 6 flows while rotating in the container main body 6, and particles contained in the air are collected in the liquid by a centrifugal separation method.

[Supply of liquid to particle counter in liquid]
Further, the flow control unit 40c outputs a signal indicating that the roller pump 38 is operated. When the signal is input, the roller pump 38 rotates the roller 38a. As the roller 38a rotates, the liquid in the container body 6 is sucked. The sucked liquid flows to the particle counter 4 through the pipe 34. Further, the liquid whose number of particles has been measured by the particle counter 4 flows to the roller pump 38 through the tube 36 and is discharged outside as waste liquid. At this time, the flow rate of the liquid flowing through the pipe 34 and the tube 36 is, for example, 10 mL / min.
As described above, the roller pump 38 is operated, so that the liquid in the collector 2 can flow toward the particle counter 4.

[Measurement of particles by liquid particle counter]
The flow control unit 40c outputs a signal to the particle counter 4 (particle number counting unit 4b) to start measuring the number of particles.
When the above signal is input, the particle counter 4 measures the number of particles contained in the liquid that has flowed through the pipe 34. In addition, when air bubbles are included in the liquid, a method for distinguishing the air bubbles from the particles is generally known. For this reason, the particle counter 4 may execute the above identification method when measuring particles.

The measured number of particles is displayed on the display 40a of the controller 40, for example. Further, the controller 40 stores the time series data in a storage medium in the controller 40, and displays a graph indicating the change state on the display 40a. A PC (personal computer) may be connected to the controller 40. In this case, a graph showing the number of particles measured by the particle counter 4 and the state of change may be displayed on the display of the PC.
The manager of the clean room can grasp the clean state in the clean room by monitoring the number of particles displayed on the display 40a and the transition of the time-series number of particles.
In addition, as described above, the controller 40 can generate an alarm when a preset value is exceeded, and can notify the operator of this.

  The flow control unit 40c outputs a signal to stop the roller pump 38 that is operating. When this signal is input to the roller pump 38, the roller pump 38 stops the rotation of the roller 38a. Thereby, discharge of the liquid from the container main body 6 is stopped.

Thus, according to the particle counting system 1 of the present embodiment, the supply of the liquid by the liquid container 30 and the discharge of the liquid from the collector 2 (container body 6) are controlled by the controller 40.
For this reason, after the collection of the particles by the collector 2 is completed, it is not necessary for the operator to install the collected sample in the particle counter 4, and from the collection of the particles to the measurement of the number of particles is automatically performed. Can be done.
Therefore, the operator (administrator) simply sets the measurement conditions in the controller 40 and measures the number of particles continuously for 24 hours, or measures the number of particles intermittently at a predetermined interval (for example, one hour interval). Can be done.

Moreover, in this embodiment, the method of collecting the particle | grains in air in the liquid (about 10 mL) in the liquid container 6 is employ | adopted. Therefore, for example, even if the air is sucked at a flow rate of 100 L / min or 300 L / min, the particles contained therein are concentrated to 10 mL of liquid and collected.
As a result, the particle counter 4 may measure 10 mL of liquid that is sufficiently smaller than the amount of air sucked. Therefore, it is possible to significantly reduce the measurement time and to use a submerged particle counter that can be measured at a general flow rate, compared with the case where particles are measured by directly taking air into the particle counter 4. it can. Further, it is not necessary to adjust the output of the laser beam by the light emitting device 12 according to the amount of air to be sucked. Furthermore, according to the particle counting system 1 of the present embodiment, since the number of particles can be measured without depending on the amount of sucked air, the sensitivity of the particle diameter can be maintained.

〔Measurement procedure〕
Next, a method for measuring particles in the particle counting system 1 of the present embodiment will be described.
In the particle counting system 1, the collection by the collector 2 and the measurement by the particle counter 4 can be executed continuously or intermittently. In the following, first, a method for continuously executing the collection and measurement will be described.

(Continuous measurement)
FIG. 4 is a flowchart showing a procedure for continuous measurement.
The above-described “continuously executed” method is a method in which the collection of particles by the collector 2 and the measurement of the number of particles by the particle counter 4 are simultaneously performed, and the measurement is continuously performed for a predetermined time (for example, 24 hours). To measure. Hereinafter, this method is referred to as “continuous measurement”.

  Step S100: The flow rate controller 40c starts supplying pure water (liquid) to the liquid container 30.

Next, the flow controller 40c opens the valve 44 and operates the roller pump 38. The roller pump 38 causes the liquid supplied to the container body 6 to flow from the pipe 34 toward the tube 36 by rotating the roller 38a. The inside of the pipe 34, the particle counter 4 and the tube 36 is filled with pure water.
At this time, based on the output signal of the liquid amount sensor 42, the controller 40 supplies liquid to the liquid container 30 so that the liquid in the container body 6 of the collector 2 can maintain a predetermined amount (10 mL). The amount of supply is controlled.

  The roller pump 38 causes the liquid flowing through the pipe 34, the particle counter 4 and the tube 36 to flow at a flow rate of 10 mL / min, for example. The suction amount (10 mL / min) by the roller pump 38 is adjusted by a valve 44. If the flow rate can be sufficiently adjusted by the roller pump 38, the valve 44 may be omitted.

  Further, without using the liquid amount sensor 42, the controller 40 determines in advance the time (liquid distribution time) from when the roller pump 38 is operated until the interior of the pipe 34, the particle counter 4 and the tube 36 is filled with pure water. You may remember it. This liquid distribution time can be set based on, for example, the total length of the pipe 34 and the tube 36 and the suction amount by the roller pump 38.

Step S102: The flow controller 40c causes the collector 2 to start sucking air. The flow rate controller 40c causes the particle counter 4 to start measuring particles.
The suction device 8 of the collector 2 sucks the air in the clean room at a flow rate of 300 L / min, for example. Further, the particle counter 4 irradiates the pure water flowing at a flow rate of 10 mL / min with laser light to detect the scattered light of the particles, and measures the number of particles based on the detected scattered light.

  Step S104: When a predetermined time (for example, 24 hours) has elapsed since the start of air suction and particle measurement, the flow rate controller 40c supplies air to the collector 2 and the particle counter 4, respectively. The suction and particle measurement is terminated. Note that the measurement by the collector 2 and the particle counter 4 may be terminated manually by the operator.

Step S106: Next, the flow rate controller 40c stops the supply of pure water to the liquid container 30. However, the operation of the roller pump 38 continues, and all of the pure water in the container body 6, the pipe 34, the particle counter 4, the tube 36 and the roller pump 38 is discharged to the outside as waste liquid.
Finally, the flow control unit 40c closes the valve 44 and stops the roller pump 38, and ends this process.

  Note that the particle counting system 1 of the present embodiment may include a device that automatically supplies pure water to the liquid container 30. In such a configuration, there is no possibility that the pure water in the liquid container 30 is depleted, so that it is suitable for constant monitoring.

FIG. 5 is a graph showing the transition of the number of particles measured by continuous measurement.
The measurement state of particles by continuous measurement is displayed on, for example, the display 40a of the controller 40 or a display of a PC (not shown) connected to the controller 40. Further, the controller 40 can generate an alarm when a preset value is exceeded, and inform the operator of this.

The vertical axis shown in the graph in FIG. 5 indicates the number of particles contained in the liquid flowing at a predetermined flow rate, and the horizontal axis indicates the measurement time. Moreover, the reference value of the number of particles is indicated by a horizontal line.
For example, clean air is supplied to the clean room, and the clean room is almost kept clean. For this reason, the number of particles measured by the particle counter 4 is substantially constant.

  However, in the part surrounded by the broken line in FIG. 5, the number of scattered light detections, that is, the number of particles has increased dramatically, exceeding the reference value. In this case, the administrator can grasp that the cleanliness in the clean room is lowered.

Thus, in the continuous measurement, “particle collection by the collector 2” and “particle measurement by the particle counter 4” can be performed simultaneously. Therefore, it is possible to monitor the transition of the number of particles that are continuously measured and suspended in the clean room.
Further, since the liquid collected by the collector 2 is immediately supplied to the particle counter 4, the particle counter 4 can measure the number of particles in the air in real time. Note that the particle counting system 1 of the present embodiment may include a device that automatically supplies pure water to the liquid container 30. Such a configuration is suitable for continuous monitoring because there is no possibility of depletion of pure water in the liquid container 30.

In the measurement method, the example using the liquid amount sensor 42 has been described. However, the measurement can be continuously performed without using the liquid amount sensor 42.
That is, the liquid container 30 supplies the liquid at a constant flow rate (10 mL / min), and the roller pump 38 similarly causes the liquid to flow at a constant flow rate (10 mL / min).
Accordingly, (1) the time required for the pure water to be filled in the pipe 32 in advance, (2) the time required for the pure water to reach a predetermined amount in the container body 6, and (3) the pipe 34 and the tube 36. By setting the time required for filling with pure water in the controller 40 based on the above-described flow rates, the controller 40 allows the liquid container 30, the collector 2, the particle counter 4, and the roller pump 38. Can be operated at a predetermined timing.

[Intermittent measurement]
Next, a method for intermittently collecting and measuring particles will be described.
FIG. 6 is a flowchart showing the procedure of intermittent measurement. Specifically, the above-mentioned “intermittently executing” method is a method of intermittently executing this cycle at a predetermined interval when the process from the collection of particles to the completion of measurement is defined as one cycle. is there. Hereinafter, a method of intermittently repeating the above cycle is referred to as “intermittent measurement”. Note that this intermittent measurement includes a case where measurement is completed in one cycle (single measurement).

Step S200: The flow rate controller 40c starts supplying pure water (liquid) to the liquid container 30.
Next, the flow controller 40c opens the valve 44 and operates the roller pump 38. The roller pump 38 rotates the roller 38 a to flow the liquid supplied to the container body 6 from the pipe 34 toward the particle counter 4 and the tube 36. The insides of the pipe 34, the particle counter 4 and the tube 36 are filled with pure water.
At this time, the liquid amount sensor 42 controls the supply amount of the liquid to the liquid container 30 so that the liquid in the container body 6 of the collector 2 can maintain a predetermined amount (10 mL). Good.

  The roller pump 38 causes the liquid in the pipe 34, the particle counter 4 and the tube 36 to flow at a flow rate of 10 mL / min, for example. The suction amount (10 mL / min) by the roller pump 38 is adjusted by a valve 44. If the flow rate can be sufficiently controlled by the roller pump 38, the valve 44 may be omitted.

Step S202: Next, the flow controller 40c ends the supply of pure water to the liquid container 30. At this time, the flow rate controller 40c closes the valve 44 and stops the roller pump 38.
At this time, 10 mL of pure water is stored in the container body 6, and the pipe 34, the particle counter 4, and the pipe 40 are also filled with pure water.

  Step S204: The flow rate controller 40c causes the collector 2 to start sucking air. The collector 2 sucks air at a flow rate of 300 L / min and collects particles contained in the air in pure water by a centrifugal separation method.

  Step S206: The flow rate control unit 40c stops the suction of air by the collector 2 when a predetermined time has elapsed.

Step S208: Next, the flow rate controller 40c causes the particle counter 4 to start measuring particles.
Specifically, the flow control unit 40c opens the valve 44 and operates the roller pump 38. Thereby, the pure water in the container body 6 flows to the particle counter 4 through the pipe 34. The particle counter 4 performs measurement until all the liquid in the container body 6 and the pipe 34 is discharged to the outside. That is, the time required until all the liquid is discharged to the outside is the measurement time.

  The pipe 34 and the particle counter 4 are previously filled with pure water in step S200. For this reason, the measurement by the particle counter 4 is started after the collection of the particles by the collector 2 is completed based on the time required for all the pure water previously filled in the pipe 34 to flow into the tube 36. You may set the time (interval) required until it is done.

Step S210: The flow rate controller 40c stops the measurement by the particle counter 4 when the measurement time has elapsed.
The measurement time is set in the controller 40 based on the amount of liquid sucked by the roller pump 38 (10 mL / min). Alternatively, the particle counter 4 may be set.
The flow rate controller 40c closes the valve 44 and stops the roller pump 38.

Step S212: The flow control unit 40c determines whether or not the next measurement is reserved. If the next measurement is reserved (Yes), step S200 is executed when the reservation time has arrived.
On the other hand, when the next measurement is not reserved (No), the flow control unit 40c ends this process. The flow rate control unit 40c may output a signal indicating that the power of the particle counter 4 is turned off when the process is terminated. When this signal is input to the particle counter 4, the particle counter 4 turns off the power.

  FIG. 7 is a graph showing the transition of the amount of liquid in the container body 6. Here, the transition of the amount of liquid in the container body 6 for one cycle is shown.

The vertical axis shown in FIG. 7 indicates the amount of pure water in the container body 6. The horizontal axis indicates the elapsed time since the supply of pure water by the liquid container 30 was started.
Pure water in the container body 6 reaches a predetermined amount (10 mL) 30 seconds (0.5 minutes) after the supply of pure water by the liquid container 30 is started.

  Next, particles in the air are collected by the collector 2. In the intermittent measurement, since pure water is not supplied from the liquid container 30 while the particles are collected by the collector 2, the amount of pure water in the container body 6 is kept almost constant. I'm leaning.

Here, the time required for collecting particles by the collector 2 is 2 minutes (600 L of air). When the collection of particles by the collector 2 is completed, the measurement of particles by the particle counter 4 is started. At this time, the roller pump 38 operates and the pure water in the container body 6 flows to the particle counter 4 through the pipe 34.
Here, the time required for pure water containing particles to reach the particle counter 4 from the collector 2 is considered. Therefore, the particle counter 4 starts measurement 30 seconds after the collection of the particles by the collector 2 (0.5 minutes later).

  Thus, even during intermittent measurement, it is not necessary for the operator to attach the sample (liquid containing particles) collected by the collector 2 to the particle counter 4. For this reason, for example, in order to examine the transition of the number of particles floating in the clean room, it is possible to perform intermittent measurement such as measurement for 30 minutes and measurement for 24 hours at intervals of 1 hour.

As described above, according to the particle counting system 1 of the present embodiment, it is possible to perform quick measurement while efficiently collecting particles in the air.
For example, when an air particle counter that directly measures the number of particles in the air is used, the measurement time becomes longer corresponding to the flow rate of the sucked air.
In contrast, in the particle counting system 1 of the present embodiment, as is apparent from the graph shown in FIG. 7, one cycle is required from the start of liquid supply until the measurement of the number of particles is completed. The time is about 4 minutes for 600 L of air. In the particle counting system 1 of the present embodiment, the time efficiency required for measuring the number of particles increases as the collection time in one cycle increases.
For example, the flow rate of the liquid flowing through the particle counter 4 is 10 mL / min even if the amount of air is increased. Therefore, quick measurement can be performed without depending on the flow rate of the air sucked by the collector 2.

  Moreover, according to the particle counting system 1 of the present embodiment, particles contained in the air sucked by the collector 2 are taken into the liquid by a centrifugal separation method. For this reason, compared with the method in which the particles in the atmosphere sent by the pump are stored in pure, the collector 2 can collect even particles smaller than 1 μm in the liquid.

  The present invention is not limited to the embodiments described above, and can be implemented with various modifications. For example, the particle counter 4 may measure the number of biological particles from particles contained in the liquid using an autofluorescence phenomenon. In this case, even if bubbles are included in the liquid, the particle counter 4 distinguishes between the scattered light reflected by the bubbles and the fluorescence emitted from the biological particles because the wavelength lengths thereof are different from each other. be able to. That is, the particle counter 4 can detect only fluorescence. For this reason, the number of biological particles can be measured.

  Further, the controller 40 of the present embodiment has been described as an apparatus separate from the particle counter 4, but may be integrated with the particle counter 4.

  In the intermittent measurement in the particle counting system 1 of the present embodiment, the number of particles in the air taken in by the particle counter 4 can be measured. Regarding the intermittent measurement, assuming that the particle collection efficiency is not 100%, the particle counter 4 may be provided with a means for correcting the collection efficiency obtained in advance by a test or the like.

1 Particle Counting System 2 Collector (Air Particle Collector)
4 Particle counter (particle counter in liquid)
30 Liquid container 32 Piping (first flow path)
34 Piping (second flow path)
36 Tube (third flow path)
38 Roller pump (pump)
40 controller (flow control device)
40c Flow control unit 42 Fluid volume sensor 44 Valve

Claims (6)

An air particle collector that performs a collecting operation of taking ambient air into a container containing liquid and collecting particles in the air with the liquid;
A series of liquid inlet / outlet operations for discharging the liquid after the collecting operation from the air particle collector while supplying new liquid for the collecting operation to the air particle collector. A liquid entry / exit operation execution means to be executed;
A particle counting system comprising: a liquid particle counter that measures the number of particles contained in the liquid discharged from the air particle collector in accordance with the series of liquid entering and exiting operations. The particle counting system of claim 1.
The liquid entry / exit operation executing means includes:
A liquid container for storing the new liquid supplied to the air particle collector;
A first flow path for flowing the liquid from the liquid container toward the air particle collector;
A second flow path for flowing the liquid discharged from the air particle collector toward the liquid particle counter;
A third flow path for flowing the liquid after the number of particles is measured by the submerged particle counter;
A pump that is disposed on the third flow path and causes the liquid to flow from the second flow path toward the third flow path via the submerged particle counter;
The amount of the liquid supplied to the air particle collector by the liquid container and the flow rate of the liquid from the second channel to the third channel via the liquid particle counter by the pump A particle counting system comprising a flow rate control device for controlling the flow rate. The particle counting system according to claim 2,
The pump is
A particle counting system, wherein the liquid is flowed at a flow rate smaller than a flow rate of air taken into a container of the air particle collector. The particle counting system according to claim 2 or 3,
The flow controller is
While the trapping operation is performed by the air particle collector, the pump is operated to supply the liquid after the trapping operation while supplying a new liquid to the liquid container. A particle counting system, wherein the air particle collector is discharged to the second flow path. The particle counting system according to claim 2 or 3,
The flow controller is
The particle count, wherein after the collection operation by the air particle collector is completed, the liquid after the collection operation is discharged from the air particle collector to the second flow path. system. The particle counting system according to any one of claims 2 to 5,
The liquid entry / exit operation executing means includes:
A liquid amount sensor that is disposed on the first flow path and detects the amount of the liquid supplied to the air particle collector;
The flow controller is
A particle counting system that controls the amount of the liquid supplied to the air particle collector by the liquid container based on the amount of the liquid detected by the liquid amount sensor.